Momsen lung
(重定向自Escape lung)

The Momsen lung was a primitive underwater rebreather used before and during World War II by American submariners as emergency escape gear. The Momsen lung was invented by Charles B. Momsen (nicknamed "Swede"). Submariners would train in an 80 ft (24 m) deep Escape Training Tank at New London or Pearl Harbor using this apparatus. It was first introduced as standard equipment on P- (Porpoise-) and Salmon-class boats.